We've been teaching the "leave it" command to our vacuum cleaner 9 mo. old puppy since he came to us at 8 weeks. We've had 4 different trainers try to help us with this to no avail. He will leave it if we are there to give the command but if we don't see him go after something he'll pick it up. This is true for leaves, stones, wood mulch, kleenex, etc. Two major problems are that at his doggie daycare the play area is mulched and if noone sees him pick up the object he could choke and eating leaves out on our deck. Also, he will listen to the "drop it" command when playing fetch but if he picks something up off the ground he locks on and we have to pry it out of his mouth. Any suggestions?